Sympathetic and parasympathetic nerves ( have opposite effects) ▪Two-stage neural paths: neuron exiting the CNS synapses on a second-stage neuron before the target organ▪Autonomic Nervous System○Peripheral Nervous System (PNS) General Layout of the Nervous System Chapter 3: The Anatomy of the Nervous System Wednesday, January 13, 20161:10 PMMidterm Page 19
Major Divisions of the Nervous System This is a great diagram for you to practice you knowledge concerning the organization of nervous system. •Notice that the nervous system is a system of twos. •Meninges, Ventricles, and Cerebrospinal Fluids (CSF) Dura mater: tough outer membrane○Immediately inside the dura matter▪Underneath is subarachnoid space - contains many large blood vessels and cerebrospinal fluid▪Archnoid membrane: web-like○Pia mater: adheres to CNS surface○The CNS is encased in bone and covered by three meninges•MeningesMidterm Page 20
The brain dose not have pain receptors. ○Meninges have pain receptors - source of pain. ○Brain goes from functionally weighing 1300g to approximately 50g. ○With some missing you suffer from ragging headaches and experience stabbing pain ○Fluid serves as a cushion•Buoyancya.Protection b.Chemical Stability c.Clearing Wasted.Function •Cerebrospinal Fluid (CSF) Absorption of cerebrospinal fluid from the sub-archinoid space into a major sinus. ○Buildup of fluid in the ventricles causing the walls of the ventricles, and thus the entire brain, to expand, producing a condition treated by draining the excess fluid from the ventricles•HydrocephalusVentriclesMidterm Page 21
We don't want any blockage of the fluids that will cause increased pressure and you can die from this•are often measured for certain neurodegenerative diseases - CNS begins to waste away.○Empty spaces fill with fluid and become larger and larger.○Schizophrenia does this, which suggests that it might be a neurodegenerative Some think the cells are getting smaller thus there's still a debate. ○Lateral Ventricles•i.e. recall L-Dopa is used as a precursor to dopamine to bypass BBB▪The blood -brain barrier (BB):tightly packed cells of blood vessel walls prevent the entry of many molecules○Some large molecules that are critical for normal brain function are actively transported through cerebral blood vessel walls. ○Many CNS disorders are associated with impairment of the blood-brain barrier, which adds to the symptoms of the disorders ▪Head trauma can disrupt the BBB and result transfer of protein and other foreign matter into the brain space. ○Chemical Protection Protecting the Brain Skull ○Meninges○Cerebrospinal fluid (CSF) ○Physical ProtectionSpecialized cells for the reception, conduction, and transmission of electrochemical signals○Many sizes and shapes○Neurons•Cells of the Nervous System: Anatomy of NeuronsDifferent brain areas seem to be somewhat specialized and when we dissect those areas we see that there are defining features.